When the mother, Mónica Vega of Barranquilla, Colombia, had an ultrasound at seven months pregnant, doctors discovered she had two umbilical cords inside her. One connected baby Itzmara to Vega, but the other connected Itzmara to a mass that was her parasitic twin.

When doctors noticed this, they diagnosed Itzmara with "fetus in fetu," a rare condition where a malformed fetus is found in the body of its twin. The doctors said they needed to deliver Itzmara right away through a C-section so they could then operate on the baby. They were worried that if they didn't remove the parasitic twin inside Itzmara, the mass could grow and injure the baby's organs.

So after delivering Itzmara via C-section, the doctors performed a C-section on her too to remove the mass, which had no heart or brain. Itzmara was in good health following the surgery, Mamás Latinas reported.

The baby's condition is extremely rare

According to the National Institutes of Health, fetus-in-fetu is very rare, with only one case occurring in about every 500,000 births. Additionally, authors of one fetus-in-fetu case study published in August said only 200 previous cases of FIF had been documented in medical journals.

FIF-related tumors are usually benign but sometimes can cause health problems, which Itzmara's doctors were concerned about happening.

Not all fetus-in-fetu cases are treated right after birth

In some cases, FIF-related health problems take years to develop.

In the August case study, published in BMJ Case Reports, a 17-year-old teen in India showed up at a hospital complaining about abdominal pain and a growing lump in that same area that she said had started developing five years earlier. When doctors examined her, they found she had absorbed her parasitic twin in the womb and was having stomach pains because of it.

Doctors opened the teen's stomach through surgery and found that the tumor ran from her liver to her pelvic bone. They said it didn't create any complications with other organs in her body besides a cyst, which they removed.

In another case, a 27-year-old man recalled having a malformed mass since childhood but said it didn't cause him any pain until he was 26 years old. Doctors are unsure why this happens.